All writers know that if you pay an editor to review your manuscript, they’ll earn their fee and then some.
At the suggestion of my agent, I recently solicited the feedback of a “developmental editor” who lacerated 25 pages at a cost of $200. She says she read 50, and she was confident I’d get the hang of her comments to do my own edit on pages 26-50. This being my tenth novel manuscript, I took her advice: I read the comments twice and then waited a week and read them again. Then I took another week and rewrote chapter one.
What I learned:

1. About a third of the paid editor’s suggestions will show a ridiculous misunderstanding of your intentions, and of who you are as a writer. It was helpful to me that this hired editor suggested I read Jonathan Frantzen and Amy Bloom, her current favorites. With due respect for the commercial and/or critical success of those authors, I am not them and do not aspire to be. The editor’s willingness to tell me her preferences, made it easier for me to assess all of her criticisms with that heaping of salt.
2. Another third of the editor’s comments will be right on the money and are things I may have caught myself if I had more distance from the work being edited.
3. The final third is up for grabs: the section your writing group loved, the editor hates; the part she says is slow your group thought too fast; the details your other readers love, the editor finds cliché. Yikes! I remember once at a workshop Margot Livesey described this very problem and concluded: many editors can tell you something isn’t working about a scene or a chapter, and they may even tell you opposite things are wrong. Both editors are probably wrong about what is wrong, and right about the fact that something is wrong. It’s up to the author to find out what.
4. First chapters need to be written last. Rewritten, I suppose, is more accurate. But you know your characters so much better at the end of the novel than at the beginning–almost everything in my first chapter was a placeholder. I’d started my novel with the idea of a character who I like a lot but who to many isn’t sympathetic because she’s not the kind of mother they want her to be. I had “reported” on her plight in my first chapter because that was what I knew about her, but I hadn’t made her plight sympathetic, which surprised me, because I am sympathetic with her and I think her situation is naturally sympathetic—she gives birth to a deformed child. But my character is hardened by that situation, not softened, and I needed readers to experience events from her point of view. Rewriting my first chapter wasn’t about taking every suggestion the editor had to offer, or about becoming a different kind of writer than who I am (less, rather than more, description; witty and intelligent dialogue; interior examination; strong, crisp prose.) It was about going back and re-meeting my characters at the critical junctures at which I wanted to elicit the reader’s sympathy. I needed to put those in scene rather than reportage, no matter how sympathetic.
5. If “scene” is the lesson (duh–show, don’t just tell), the most important lesson to be taken from hiring an editor is that we absolutely need good editors–even when they’re wrong–to let us know when we’ve forgotten what we know. Distance from one’s work is critical to editing, and, because of the potential interference of ego, to responding to editing.
6. And, isn’t it great that as author, you get to decide what exactly is ‘wrong’? My week of rewriting was fun, and relatively easy. After all, I already knew my characters, lliked them, and where they were headed!